I got my 2001 205V last June and have had to go through about everything to get it right. The PO replaced the factory white trimmed tach with a dark gray trimmed tach and when I start the boat the LED screen will read "No Data" and that's it.

So I'm guessing it's one of two scenarios...

1) Wrong tach for boat, get the right one and it will read fine.

2) The box that controls the tach/gauges is shot and needs replaced. Note: All other gauges are fine or at least show signs of life.